Why should I wait for for 3 months after having Botox for the first time?

The 3- to 4- month waiting period between Botox sessions is just that: a recommendation. If the Botox wears off sooner than that for you, it's perfectly safe to be re-treated as soon as you need it. I hope this helps.

It usually takes around 3 months for the Botox to wear off, at which point you may wish to return to have Botox again. Depending on your facial anatomy, it might be recommended to inject a smaller doseage of Botox and then return in two weeks for a 'top-up'. This is because if you inject too much of the substance too often or too much in one appointment, there is the risk that you will experience unwanted side effects such as drooping eyelids and/or drooping brows. For this reason, it's always best for the Botox to have completely worn off before you return for your next appointment. 

There is no hard and fast rule that Botox injections be spaced out at three month intervals.  It usually takes between 2-14 days for the injection to take effect. Your board certified plastic surgeon may schedule you for a follow up at the end of a month to assess if the anticipated result is as expected or if dosages need to be adjusted. The wrinkle softening effect of Botox is temporary as the toxin is broken down by enzymes in the body and eliminated over time.  Botox injections typically last from 3-6 months before the effects are no longer seen.Kenneth Hughes, MD, Board Certified Plastic SurgeonLos Angeles, CA